Jun 1, 2011

Geo-engineering: Biomass


Traditionally, biomass has been used in four ways:
1. For industrial purposes (shelter, building materials, furniture, utensils, etc)
2. Burning (for domestic energy use such as heating, lighting and cooking, and for land clearance)
3. Conservation (left on land or added to soil as compost, to enrich soil and biodiversity, avoid erosion, etc.)
4. For food (including livestock feed, while using fertilizers and with waste dumped in landfills or sea)
In the light of rising costs of fossil fuel and climate change concerns, other uses are considered, specifically:
5. Low-footprint food (reduced meat and reduced use of chemical fertilizers, with waste processed)
6. Commercial combustion in power plants, furnaces, kilns, ovens and internal combustion engines
7. Burial
8. BECCS (Bio-Energy with Carbon Capture & Storage)
9. Biochar (Pyrolysis resulting in biochar, syngas and bio-oils)
10. Biochar + BECCS (Biochar + Bio-Energy with Carbon Capture & Storage)
Table 1. Comparison of methods to process biomass (Energy and Carbon)
CombustionBurialBECCSBiocharBiochar + BECCS
Energy - year 01.0-
Carbon - year 0-
Energy - out years0.40.4
Carbon - out years0.50.5
Total 0.9 0.9 1.6 1.9 2.3
Above table by Ron Larsen, from this message, shows five methods to process biomass, rated (with 1.0 being the highest score) for their ability to supply energy and for their ability to remove carbon from the atmosphere.
Above table shows that each way to process biomass waste has advantages and disadvantages:
6. Combustion may seem attractive for its supply of energy, while having negative impact due to emissions
7. Burial can minimize emissions, but it doesn't provide energy, in fact it costs energy
8. BECCS can score high on immediate energy supply as well as on avoiding carbon emissions
9. Biochar scores well regarding immediate energy supply and emissions, with additional future benefits
10. Biochar + BECCS has all the benefits of biochar, while also capturing and storing pyrolysis emissions
The table below also incorporates above-mentioned traditional use of biomass, while using a wider footprint, i.e. with scores not only reflecting the ability of the method to remove carbon from the atmosphere, but also looking at emissions other than carbon.
Table 2. Comparison of ten uses of biomass (Energy and Footprint)
Energy - year 0Footprint - year 0Energy - out yearsFootprint - out yearsTotal
Food-0.3 -0.3
Low-footprint food0.0
Burial-0.11.0 0.9
BECCS0.8 0.8 1.6
Biochar0.5 0.50.4 0.51.9
Biochar +BECCS0.5 0.9 0.4 0.52.3
Biochar gets its positive "out years" scores for increasing vegetation growth over time, as it improves soil's water and nutrients retention, while also reducing the need for chemical fertilizers.
These qualities of biochar are also helpful in efforts to bring vegetation into the desert by means of desalinated water, as proposed by a number of scientists. A study by Leonard Ornstein, a cell biologist at the Mount Sinai School of Medicine, and climate modelers David Rind and Igor Aleinov of NASA's Goddard Institute for Space Studies, all based in New York City, concludes that it's worth while to do so.
They envision building desalination plants to pump seawater from oceans to inland desert areas using pumps, pipes, canals and aqueducts. The idea is that this would result in vegetation, with the tree cover also bringing more rain -- about 700 to 1200 millimeters per year -- and clouds, which would also help reflect sunlight back into space.
This would not only make these deserts more livable and productive, it would also cool areas, in some cases by up to 8°C .
Importantly, vegetation in the deserts could draw some 8 billion tons of carbon a year from the atmosphere -- nearly as much as people now emit by burning fossil fuels and forests. As forests matured, they could continue taking up this much carbon for decades.
The researchers estimate that building, running, and maintaining reverse-osmosis plants for desalination and the irrigation equipment will cost some $2 trillion per year.

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